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Rocketry at the Makerspace!

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  • Rocketry at the Makerspace!

    Hey all! A hobby of mine over the past while has been rocketry projects, I built this project over the summer and wanted to share it.
    This project was largely built out of re-purposed materials or ones that I created directly at the Makerspace.



    It was 1.4 meters tall (55"), 83 mm diameter (3") and flew on a G-class G80 motor - which in this case is a 109 Newton (24lb) peak thrust motor. This is about the largest motor one can buy without special certifications.

    All in the rocket weighed about 1kg (2 lb) and should have flown to about 350 meters (1150 feet) and 315 km/h (195 mph). The idea was to build a simple, but large rocket out of a shipping tube that my Mcmaster Carr order arrived in. With this engine, a lighter and smaller build would have been faster or go higher, you can easily go supersonic on these motors. Unfortunately I lost sight of it at launch, had issues with the parachute and despite hours of searching it was never found.

    Regardless here's some photos of the build!

    Tools I used:
    Open Rocket - free software that helps with all aspects of design, estimates performance and calculates stability margins. Get it here> http://openrocket.info/
    Fusion 360 - not a must, but an extremely useful tool for creating the laser cut & 3D printed pieces.
    3D printer - for making the nose cone.
    Laser cutter - for making the fins, centering rings and ejection charge baffles.
    Paint booth - the paint booth in the Fab Shop is ventilated and free from dust and breeze; problems I would have had in my garage or yard.
    Vinyl Cutter - thanks to Vaughn for the sick decals!

    Starting out I first used OpenRocket to create my design and make sure it was going to fly nice and straight. The principles of this is that the center of mass has to be ahead of the center of pressure, just like say a Shuttlecock used in badminton. The more weight to the front and the more drag in the back the more stable it is. These calculations can be done by hand, but it's super tedious and OpenRocket takes care of that for you. On top of that you can figure out ejection charge delay times, and of course get estimates on speed and altitude.

    Getting the fins to the correct size, adding weights or moving around weights is the key to making sure things will fly straight up, rather than say straight at yourself.

    This program sounds like it might be super complicated, but honestly its pretty simple. In fact my 12 year old son was able to pick it up with a little bit of training and design his own that he later built and flew!

    Click image for larger version  Name:	 Views:	1 Size:	339.7 KB ID:	332

    More in the next post...
    Last edited by Garret H; 10-26-2018, 11:44 PM.

  • #2
    After initial design I loaded everything into Fusion 360, drew some more detail and created all the necessary parts I would need. There is a little back and forth in this process, between F360 and OpenRocket, as well as weighing all the components and back checking for accuracy, but really the work here isn't more than an afternoon. As you draw the parts its an easy and fast process to export DXF's and STL's to the laser cutter and 3D Printer.

    Designing the fins, a fin jig, and the finished fin can as its being installed:

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    • #3
      After installing the fins it's best to strengthen them by adding some fillets between the fins and the body tube. Some 2 part JB weld epoxy is easy to work with and makes for a very strong connection. Some masking tape can be used to make for nice clean lines. Next to fill in seams on the cardboard body tube a diluted mix of Elmer's Carpenter's filler & water is used and then sanded. The rocket after filling can be seen here, along with a super handy banana to give a sense of scale.

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      • #4
        I built an ejection baffle for this rocket, this helps slow the hot gas from the black powder ejection charge down mixes with air and helps prevent the parachute from getting roasty toasty. This is where having a laser cutter pays dividends! This type of part would be very time consuming to built by hand but its a 5 second job on the laser. Alongside this a nose cone was 3D printed.

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        • #5
          After final assembly the rocket was sent out to the paint booth at the Makerspace, and done up in a 2-tone paints scheme. Vaughn made some awesome Makerspace decals for this rocket and it was all finished up!


          And then, it was launched. I wanted to capture the blue flame of this motor by launching it at dusk, unfortunately this decision came back to haunt me as it disappeared from sight. I did at least manage to get a couple shots from liftoff, unfortunately the on board video camera was lost

          But, one failure is not the end. This rocket shall be reborn, lighter, faster, higher, and with a significant suite of electronics to provide redundant altitude dependent parachute deployments, telemetry tracking, and a GPS tracker.

          My hope for this next build isn't just to fly the rocket, but also to carry a payload from the Makerspace community!

          If anyone's interested in doing a similar project or building this exact same one, hit me up. I can post tutorials, files, dxf's or whatever you need!
          Attached Files
          Last edited by Garret H; 10-26-2018, 11:53 PM.

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          • #6
            Well I rebuilt this thing, this time using some tubes that give a huge amount of room for payload.

            I've got 18" long x 3" diameter free to put something in there. Any suggestions?

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            • #7
              I'm a fan of stuffed animals with parachutes. Surplus 2010 Olympic mascots work well in my experience, though there has been at least one Quatchi left in a very tall tree. Charlie Brown suffers from kite eating trees, I suffer from rocket eating trees, regardless of launch area.
              Board Member - Treasurer

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